The invention starts out from a device disclosed in DE 297 19 564 U1.
The prior art device described in DE 297 19 564 U1 is equipped with guide rolls that guide the lower member of a spacer frame between two opposing nozzles by bearing against its two flanks or sidewalls with their running surfaces (outer circumferential surfaces), while at the same time the nozzles apply an adhesive or sealant on the same two flanks. Relative to the specified conveying direction, these guide rolls are located ahead of the nozzles. In order to prevent slippage between the conveyor belt and the spacer frame which could result in uneven coating, the known device is equipped with pressing rolls that can be pivoted into position both ahead of and after the nozzles relative to the conveying direction, and can apply pressure on the upper side of the lower member of the spacer frame, thereby increasing pressure on the conveyor belt on which the lower member lies.
However, these pressing rolls are not suitable for guiding the spacer frame laterally.
Moreover, they have to be pivoted out of the motion plane of the spacer frame when upwardly projecting members of the spacer frame approach the pressing rolls during the coating process. Furthermore, when coating spacer frames with crosspieces, the pressing rolls have to be temporarily pivoted out of the motion plane of the spacer frame to allow the crosspieces to pass the pressing rolls. This could compromise the frictional connection between spacer frame and conveyor belt for spacer frames with closely spaced crosspieces.
In order to overcome these disadvantages, DE 297 19 564 U1 discloses an additional device for coating the flanks of spacer frames for insulating glass panes with adhesive or sealant. This additional device is comprised of a conveyor with nozzles on both sides of the conveyor for applying adhesive or sealant on the flanks of the spacer frame, a support above the conveyor for supporting upwardly projecting members of the spacer frame, and pressing rolls that can apply pressure on the upper side of the lower member of the spacer frame, thereby increasing pressure on the conveyor belt on which the lower member lies, and that can be pivoted away again. In this additional device the pressing rolls differ in that they do not bear on the upper side as first described, but only on the lateral edges of the upper side of the lower member of the spacer frame. This proposal makes use of the fact that the crosspieces are generally narrower than the spacer frame itself, so that pressing rolls that only barely reach into the spacer frame by contacting only the lateral edges of the upper side of the lower member of the spacer frame can pass the narrower crosspieces without having to be lifted off first
In a first exemplary embodiment, DE 297 19 564 U1 proposes stepped pressing rolls whose smaller diameter portion contacts the outer edge of the upper side of the spacer frame member and whose ring area, oriented perpendicular to the axis of rotation, contacts the flanks of the hollow cross-section of the spacer frame member. This exemplary embodiment is advantageous in that the pressing rolls, although only bearing down on an area on the upper edge of the frame member, cannot slide off the frame member, since the ring area of the pressing roll adjacent to the flank of the frame member is constrained by the flank. However, It is disadvantageous in that the width of the spacer frame has to be precisely known before the pressing rolls can be precisely set down on the lower member of the spacer frame. Moreover, the ring area of the pressing rolls rubs against the spacer frame which-causes some wear and tear.
In a second exemplary embodiment of DE 297 19 564 U1 pressing rolls with horizontal axes of rotation and conical running surfaces are disclosed. These pressing rolls can be pivoted down and positioned on the edge of the upper side of the lower spacer frame member. Here also the width of the spacer frame has to be precisely known in order to correctly position the rolls for them, on the one hand, to reach into the spacer frame sufficiently and to contact the upper edge of the frame member reliably, but on the other hand, to reach not too far into the spacer frame, so that they do not collide with the crosspieces. Furthermore, in case the hollow sections of the frame have sharp edges, the running surfaces of the pressing rolls may wear down resulting in unsteady running of the spacer frame.
It must be ensured that the pressing rolls in both exemplary embodiments pass both the thickest crosspieces as well as slightly eccentric ones without colliding with them.
The object of the current invention is a device of the type described in the beginning, where slippage-free transport of spacer frames, even spacer frames with crosspieces, during coating is achieved by simpler means.
This object is solved by a device for coating sidewalls or flanks of a spacer frame for insulating glass panes with an adhesive or sealant, in which the spacer frame consists of a plurality of members; comprising:
a conveyor that defines a conveying direction and on which one of said members of the spacer frame is laid down to be conveyed by said conveyor;
a support provided above the conveyor for supporting those members of the spacer frame that project upwardly from the conveyor;
opposing nozzles provided on both sides of the conveyor for applying said adhesive or sealant to the flanks of the respective member of the spacer frame laid down on the conveyor;
and guide rolls located above the conveyor that guide the respective member of the spacer frame laid down on the conveyor by bearing against both flanks of this member with their outer circumferential surface, or at least with an edge of said circumferential surface;
wherein at least a subset of the guide rolls is so designed and/or arranged that during the conveying process as they roll along the flanks, they exert on the flanks with their outer circumferential surface or with the edge thereof an additional force that is directed towards the conveyor.
Advantageous further embodiments of the invention are the subject of the dependent claims.
According to the invention the guide rolls that contact the flanks of the lower member of the spacer frame with their running surface (outer circumferential surface), or at least with their edge, are designed and/or arranged so that they exert on the flanks of this member of the spacer frame a force that is directed against the conveyor during the conveying and coating process. This may be achieved by applying a force on the guide rolls, after clamping the lower member of the spacer frame between them, and directing this force against the conveyor, whereby the force may not exceed the static frictional force between the guide rolls and the flanks of the spacer frame. In this manner the guide rolls, only by contacting the flanks of the spacer frame, can also affect the frictional connection between spacer frame and conveyor in order to eliminate slippage between the conveyor and the spacer frame.
The conveyor is customarily configured as an endless, driven conveyor belt. The conveyor belt is dragged over an essentially horizontal support area that supports and guides the belt from below. Also conceivable is a conveyor belt in the form of a horizontal row of synchronized driven rollers with essentially horizontal axes of rotation.
Especially advantageous and therefore preferred is the use of guide rolls whose axis of rotation is inclined against the conveying direction of the conveyor. Because of the inclination the guide rolls exert a force that is directed against the conveyor while and by rolling on the flanks of the lower member of the spacer frame. This force increases as the axis of rotation of the guide rolls is tilted from the well-known vertical to a tilted position that is inclined against the conveying direction. Since with increasing inclination friction between the guide rolls and the flanks of the spacer frame member increases also, a small inclination is preferred. It follows that the angle between the axis of rotation of the guide rolls and the conveying direction is preferably at least 80 degrees and not more than 89 degrees. Preferably the angle between the axis of rotation and the conveying direction is at least 85 degrees, or better 86 to 88 degrees.
In the invention on hand cylindrical guide rolls are preferred. Their axis rotation is best inclined exclusively in the conveying direction, because the outer circumferential surface of the guide roll then contacts the flanks not only with its edge but also along a straight line on its outer circumferential surface. Therefore static friction between the guide rolls and the flanks of the spacer frame is greater and a more favorable force transfer on the flanks is achieved.
Furthermore, it is possible to configure conical guide rolls. In this case the angle between the cone axis and the flanks of the spacer frame is best chosen as one half of the out-to-out cone angle, so that the outer surface of the guide rolls can roll along the flanks of the spacer frame with maximum possible static friction. In this case also, the desired effect is essentially due to the inclination of the axis of rotation against the conveying direction, whereby the conical shape can indeed contribute to the force exerted on the flanks and directed against the conveyor.
The invention has significant advantages:
Basically, pressing rolls are not required. Only preferably but not at all by necessity, an additional holding down roll ahead of the nozzles relative to the conveying direction is provided in one exemplary embodiment of the invention. This holding down roll may not only be pivoted down on the lateral edge of the upper side of the lower edge of the spacer frame member (as taught in DE 297 19 564 U1) but may be pivoted down centrally on the upper side, as already known earlier. It is to increase the frictional connection between the spacer frame and the conveyor in the beginning phase, until the guide rolls on the flanks have developed their maximum effectiveness. The guide rolls can take on this task also, (that is, strengthening the frictional connection in the beginning phase), if they are deployed so that they clamp the frame member and pull it down toward the conveyor. A device configured in this manner does not require the pressing action of any pressing roll on the upper side of the spacer frame member
Since the guide rolls bear solely on the flanks of the spacer frame, it is not necessary to know the width of the respective spacer frame beforehand. Rather, it is sufficient to engage the rolls against the flanks. Preferably they are spring-loaded against the flanks, especially by means of pneumatic piston/cylinder units.
As long as the trailing, upwardly projecting frame member is uncoated, the guide rolls may simply roll past the trailing end of the spacer frame without lifting off. This is the case for three of the four members of a rectangular spacer frame.
Since the guide rolls do not involve the upper side of the lower member of the spacer frame, spacer frames with crosspieces that are as wide, or almost as wide as the spacer frame itself can be processed with the device according to the invention.
The guide rolls contact the flanks not only in a point, but along a line on their outer circumferential surface, which results in less wear and tear due to lower pressure. The wear and tear of the guide rolls is therefore relatively minor.
Whereas in known devices guide rolls that bear exclusively against the flanks of the spacer frame are arranged solely ahead of the nozzles relative to the conveying direction, guide rolls according to the invention are arranged preferably both ahead of and after the nozzles. Whereas ahead of the nozzles the entire height of the flank is available for contact with the guide rolls, this is not the case after the nozzles. The spacing of the guide rolls after the nozzles is somewhat greater than that ahead of the nozzles and the contact area is above the nozzle openings, so that contact between guide rolls and adhesive or sealant is avoided. It has been shown that the area above the coating of adhesive or sealant is sufficient for slippage-free conveying, when the axis of the guide rolls is inclined against the conveying direction, as required. The vertical position of the guide rolls above the conveyor is preferably adjustable in order to be able to optimize the effective position of the guide rolls.
Just in case the guide rolls accidentally come in contact with the adhesive or sealant, their running surface is preferably wrapped with a fabric that repels the adhesive or sealant. Particularly effective on the running surface has been a ceramic coating whose pores are filled with a material that repels the adhesive or sealant. Suitable fillers are, e.g., a silicone or polytetrafluoroethylene, where a silicone is preferred. An added benefit of the ceramic matrix of the running surface coating is its superior wear resistance.